Designed a high-pressure gas decompression system, introduced its working principle, and established a mathematical model of the process of the gas decompression, further simulation study of high-pressure gas decompression system was made based on AMESim. The feasibility of the high-pressure gas decompression system was demonstrated, and the influence of thermal exchange with the external environment on gas energy was studied. It provides a theoretical basis for the design of the components of high-pressure gas decompression system.